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In this paper, we demonstrate a stable output single-longitudinal-mode (SLM) Erbium-doped fiber laser (EDFL) with eight selectable wavelengths. The EDFL achieves wavelength selection through a 1 × 8 arrayed waveguide grating (AWG) and generates SLM output using the passive triple subring resonator (PTSR) architecture. In the experimental measurements, we separately measured the wavelength, power, and optical signal-to-noise ratio (OSNR) for all eight channels. The experimental results show a wavelength spacing of approximately 0.8 nm, with OSNRs around 60 dB and powers around 2.5 dBm for each channel. The power and OSNR for all eight wavelengths show very little variation. Finally, we measured that the laser outputs are all SLM, and the measured linewidths are all less than 2.5 kHz.

We present an innovative method harnessing multistability within a diode-pumped erbium-doped fiber laser to construct logic gates. Our approach involves manipulating the intensity of external noise to regulate the probability of transitioning among four concurrent attractors. In this manner, we facilitate the realization of OR, AND, NOR, and NAND logic operations, aligning with the coexisting period-1, period-3, period-4, and period-5 orbits. Employing detrended fluctuation analysis, we establish equilibrium in the probability distributions of these states. The obtained results denote a substantial advancement in the field of optical logic gate development, representing a pivotal stride toward the seamless integration of an all-optical logic gate within laser oscillator-based systems. [ABSTRACT FROM AUTHOR]

This present study demonstrates the utilization of an electro‐optic modulator (EOM) to actively Q‐switch the pulses produced by an all‐polarization‐maintaining (all‐PM) erbium‐doped fiber (EDF) laser (all‐PM‐EDF laser). Electrical sine waves that produced steady microsecond pulses at 1552 nm were used to power the 10 GHz bandwidth EOM. By altering the frequency of the external modulation signal and the power of the input pump, the width of the pulses produced by the all‐PM‐EDF laser (4 μs) could be further decreased to 2.6 μs. When the modulation frequency of the all‐PM‐EDF laser was 15 kHz, the highest pulse energy that it produced (145 nJ) corresponded to its highest power output (52 mW). Therefore, sources of single‐polarization pulsed lasers that are significantly resistant to mechanical and temperature disturbances can be designed by merging the configuration of an all‐PM with an EOM. [ABSTRACT FROM AUTHOR]

This work demonstrates femtosecond pulse generations in C- and L-band regimes utilizing a gamma-aluminum oxide/polydimethylsiloxane saturable absorber (γ-Al2O3/PDMS-SA) via mode-locking technique. The γ-Al2O3/PDMS-SA has a 7.3% modulation depth and a moderate saturation intensity of 303 MW/cm2, and estimated damage threshold of greater than 8.49 and 3.57 GW/cm2 pumping intensities in C- and L-band wavelengths, respectively. In the C-band laser cavity, the generated mode-locked pulse delivered a low threshold of 28.7 mW and an ultrafast width of 622 fs. Meanwhile, a higher threshold of 108.6 mW and 942 fs pulse width were measured in the L-band laser cavity centered at 1611 nm. These demonstrations showcase a versatile feature of γ-Al2O3 as a light-absorbing material that generates ultrashort pulses in a wideband wavelength range, which could benefit future research on the metastable state of aluminum-based materials within the field of ultrafast photonics.

An interference filter is designed by cascading two Mach-Zehnder interferometers (MZIs), which is then utilized in the construction of a wavelength interval adjustable dual-wavelength Erbium-doped fiber laser (EDFL). Each MZI consists of two 3 dB optical couplers (OCs) connected in series. The input light is split into two arms at the first OC and recombined at the second OC. The first MZI (MZI 1) has a smaller free spectral range (FSR) and is used for selecting the output wavelength of the laser. The second MZI (MZI 2) has a larger FSR and forms an envelope structure on the comb-like spectrum of MZI 1. By adjusting the optical path difference between the two arms of MZI 2, the FSR of the envelope can be changed, thereby altering the interval of the output wavelengths. The implemented filter is inserted into the EDFL to achieve stable dual-wavelength output. By stretching one arm of MZI 2, the interval of the dual-wavelength can be adjusted from 4.64 to 13.94 nm, with the side-mode suppression ratio of over 44 dB for all wavelengths. [ABSTRACT FROM AUTHOR]

In this study, we demonstrate the utilization of a saturable absorber (SA) based on the Thin-Film Dititanium Tin Carbide (Ti2SnC), a novel MAX phase material, in a Q-switched erbium-doped fiber laser (EDFL) operating at 1.5 µm. The Ti2SnC was effectively integrated with an EDFL cavity to modulate cavity loss and facilitate Q-switching. The resultant SA was produced through a synergistic combination of Ti2SnC and polyvinyl alcohol (PVA), forming a thin film. The Q-switched operation exhibited high stability, achieving an impressive signal-to-noise ratio (SNR) of 65.41 dB. The laser operated within a pump power range of 67.75 mW to 115.99 mW, correlating to a laser diode current of 130–220 mA. This resulted in output power ranging from 2.33 to 6.65 mW, exhibiting a slope efficiency of 1.57%. The Q-switched laser generated pulses at a wavelength of 1531.25 nm, with the repetition rate varying from 64.18 kHz to 105.9 kHz. This corresponded to a pulse width between 5.68 and 3.00 µs. The maximum pulse energy obtained in our study was 62.80 nJ. Additionally, the 3 dB spectral bandwidth was measured to be 1.3 nm. These experimental results highlight the potential of Ti2SnC, as a cost-effective, efficient, and practical option for saturable absorbers in Q-switched fiber lasers, thereby paving the way for further developments in photonic applications.

In this work, we have demonstrated passive Q-switched and mode-locked erbium-doped fiber lasers (EDFLs) by using metal salt of cadmium chloride hydrate (CdCl2.xH2O) as a saturable absorber (SA). The mechanical exfoliation method was utilized to fabricate the CdCl2.xH2O-SA. The fabricated SA showed a modulation depth of 20% with a saturation intensity of 80 mW/cm2. At a pump power of 167 mW, the proposed Q-switched laser operated at 1542 nm with a maximum repetition rate of 127 kHz and a narrowest pulse width of 1.76 µs. The maximum output power was 23 mW with a signal to noise ratio (SNR) of 76 dB. On the other hand, the mode-locked pulses were generated within a pump power range of 91–167 mW, achieving a repetition rate of 990 kHz. The maximum pulse energy and output power were 7.3 nJ and 7.2 mW, respectively. The SA film demonstrated reliability and simplicity in the fabrication process. [ABSTRACT FROM AUTHOR]

A tapered microfiber decorated with titanium dioxide-silicon dioxide nanocomposite saturable absorber (TiO2-SiO2-SA) is demonstrated via alkali fusion method and spin-coating technique. The TiO2-SiO2-SA exhibited 17.1% modulation depth, 31.7 µJ/cm2 saturation fluence and 35.4% non-saturable loss. The TiO2-SiO2-SA was able to generate a pulse duration of 797 fs at a repetition rate of 10.39 MHz and an average output power of 16.57 mW at 1.56 μm. This work presents an enhanced pulse duration within titanium-based saturable absorbers. The high damage threshold of beyond 24.82 GW/cm2 and excellent stability are believed to have opened a new route of using nanomaterials derived from waste product for next generation ultrafast photonic applications.

We present an innovative method harnessing multistability within a diode-pumped erbium-doped fiber laser to construct logic gates. Our approach involves manipulating the intensity of external noise to regulate the probability of transitioning among four concurrent attractors. In this manner, we facilitate the realization of OR, AND, NOR, and NAND logic operations, aligning with the coexisting period-1, period-3, period-4, and period-5 orbits. Employing detrended fluctuation analysis, we establish equilibrium in the probability distributions of these states. The obtained results denote a substantial advancement in the field of optical logic gate development, representing a pivotal stride toward the seamless integration of an all-optical logic gate within laser oscillator-based systems.

We have numerically demonstrated the dynamics of dissipative soliton (DS) and conventional soliton (CS) in passively mode‐locked erbium‐doped fiber (EDF) laser. By adjusting corresponding parameters, DS could turn into inset soliton, rope soliton, and sawtooth soliton. To our knowledge, this is the first time these phenomena mentioned above have been observed. Meanwhile, CS could convert to two‐soliton molecules, three‐soliton molecules, and noise‐like pulses. When studying the convert process and dynamics of CS, we found the phase of CS is closest to 0 compared to all solitons mentioned above, which means that it can play a considerable role in fiber lasers with strict requirements on phase change. Our simulation results can contribute to a better understanding of the various soliton dynamics in passively mode‐locked EDF lasers. [ABSTRACT FROM AUTHOR]

Simultaneous generation of continuous wave (CW) laser and mode-locked pulses employing fiber lasers has not been realized so far to the best of our knowledge. The idea may have various specific applications in the field of photonics and optical communications. Therefore, we propose through numerical simulations a novel method for simultaneous generation of CW laser and train of mode-locked pulses based on two cascaded cavities of Erbium-doped fibers (EDFs) tunable in C+L-band (1555-1625 nm) connected through a fiber Bragg grating (FBG). A single 1480 nm pump is shared for pumping both EDFs by splitting the power between them. Pumping the EDF in first cavity generates a CW laser of linewidth of 0.01 nm tunable in 1555-1625 nm wavelength range using an intra-cavity tunable optical filter (TOF) as well as provides seed that is injected through the FBG for mode-locking in the second cavity. Injecting the seed and pumping into the second cavity generates a CW laser in the second cavity that can be at the same wavelength of the first cavity or at different wavelength in the range between 1555–1625 nm achieved by tuning the center wavelength of a tunable optical bandpass filter (TOBF) in the second cavity. The injected seed is also used in the mode-locking process in the second cavity to produce pulses at the selected wavelength of the TOBF. It is possible to have both CW and pulse train in the second cavity if the TOBF in each cavity has different center wavelength. Else, the first cavity will have CW light while the second cavity generates pulses at same wavelengths. A Mach-Zehnder modulator (MZM) placed inside the second cavity driven by Gaussian pulses at a repetition rate of 2 MHz realizes an active mode-locked fiber laser that generates train of pulses with full-width at half maximum (FWHM) of around 38 ns. The proposed design is optimized for the EDF length and doping concentration of Er 3 + in both of the cavities. A wide tuning of 70 nm with average output powers of 22.6 dBm and 24.6 dBm are obtained for the first cavity while average output powers of 21 dBm and 22 dBm are obtained for second cavity for coupling ratios of 10% and 20%, respectively. Optical signal to noise ratio (OSNR) varies from 81.4 to 99 dB for first cavity and from 60 to 87 dB for the second cavity over 1555–1625 nm wavelength range. Finally the effect of increasing the coupling ratio of first cavity on mode-locking process in the second cavity has been investigated. The proposed design of tunable cascaded EDFLs for simultaneous generation of CW laser and train of mode-locked pulses is cost-efficient, simple, and stable permitting a broad tuning of 70 nm in 1555–1625 nm wavelength range. [ABSTRACT FROM AUTHOR]

In this paper, we propose and experimentally validate passively mode-locked erbium-doped fiber lasers utilizing CNFs as saturable absorbers (SAs). A mode-locked pulse was observed, with a central wavelength of 1562 nm and a bandwidth of 3.56 nm after inserting the CNF film into the ring cavity. The pulse duration and repetition rates are 1.28 ps and 54 MHz, respectively. The maximum output power can reach 1.93 mW. To our knowledge, this is the first report of CNF as SA in erbium-doped fiber lasers. [ABSTRACT FROM AUTHOR]

An interference filter is designed by cascading two Mach-Zehnder interferometers (MZIs), which is then utilized in the construction of a wavelength interval adjustable dual-wavelength Erbium-doped fiber laser (EDFL). Each MZI consists of two 3 dB optical couplers (OCs) connected in series. The input light is split into two arms at the first OC and recombined at the second OC. The first MZI (MZI 1) has a smaller free spectral range (FSR) and is used for selecting the output wavelength of the laser. The second MZI (MZI 2) has a larger FSR and forms an envelope structure on the comb-like spectrum of MZI 1. By adjusting the optical path difference between the two arms of MZI 2, the FSR of the envelope can be changed, thereby altering the interval of the output wavelengths. The implemented filter is inserted into the EDFL to achieve stable dual-wavelength output. By stretching one arm of MZI 2, the interval of the dual-wavelength can be adjusted from 4.64 to 13.94 nm, with the side-mode suppression ratio of over 44 dB for all wavelengths.

A stable, single, and dual-wavelength erbium-doped fiber laser (EDFL), based on two Mach–Zehnder interferometers (MZIs), arranged in a cascade configuration, was proposed for experimental purposes. Both MZIs were assembled by splicing a capillary hollow-core fiber (CHCF) section between two multimode fibers (MMFs) segments. The novelty of this single and dual-wavelength EDFL is that the switchable operation of the laser is achieved by thermally tuning the interference pattern of one MZI and not by adjusting the polarization state inside the fiber ring cavity. The maximum measured value of SNR was 58.9 dB for the single and dual-wavelength laser emissions. Moreover, the stable output power exhibited by this EDFL, in terms of minimal power and wavelength fluctuations, at 0.05 dB and 10 pm, was detected during the single and dual-wavelength operation. It is worth noticing that switching is achieved at exact wavelength locations with a separation of 1.8 nm and not randomly, as reported by other works. These features make this switchable EDFL an appealing candidate for application in optical fiber communication systems and fiber sensing. [ABSTRACT FROM AUTHOR]

We study the supercontinuum (SC) generation from a passively mode-locked erbium-doped fiber laser (ML-EDFL) using two different samples of monolayer graphene saturable absorber (SA) onto the side-polished surface of a D-shaped fiber, characterized with 98% and 65% polarization dependent loss (PDL), respectively. By using the first 98% PDL graphene SA (setup-1), output pulse spectral profile with 11.6 nm bandwidth was obtained from the ML-EDFL and subsequently amplified using an erbium-doped fiber amplifier (EDFA) to pump 2-m highly nonlinear fiber (HNLF) and 5-m ZBLAN lengths, both fibers operating at the normal dispersion regime, which resulted in individual SC generation of 350 and 245 nm, respectively. Furthermore, the EDFA was spectrally characterized by observing their SC blue shift of the central wavelength, reaching a value of 6.9 nm at 12 dB due to dispersion gain. With the second 65% PDL graphene SA (setup-2), we could generate SC with 227 and 351 nm bandwidths using 0.5 and 2 m HNLF lengths, respectively. Because the two SC setups were highly dependent on the polarization state of the input pulse, we optimized the SC generation from setup-2 using an external polarization controller (PC), which allowed us to adjust both the spectral brightness and the broadening of the SC. • SC generation using two samples of monolayer graphene on D-shaped fibers as SA. • SC generation seeded by both different solitons profiles and polarization states. • The two previous SC generation studies were analyzed using HNLF and ZBLAN fibers. [ABSTRACT FROM AUTHOR]

This work presents a dual-wavelength C-band erbium-doped fiber laser assisted by an artificial backscatter reflector. This fiber-based reflector, inscribed by femtosecond laser direct writing, was fabricated into a single mode fiber with a length of 32 mm. The dual-wavelength laser obtained, centered at 1527.7 nm and 1530.81 nm, showed an optical signal-to-noise ratio over 46 dB when pumped at 150 mW. Another feature of this laser was that the power difference between the two channels was just 0.02 dB, regardless of the pump power, resulting in a dual emission laser with high equalization. On the other hand, an output power level and a central wavelength instability as low as 0.3 dB and 0.01 nm were measured, in this order for both channels. Moreover, the threshold pump power was 40 mW. Finally, the performance of this dual-wavelength fiber laser enhanced with a random reflector for sensing applications was studied, achieving the simultaneous measurement of strain and temperature with sensitivities around 1 pm/με and 9.29 pm/°C, respectively. [ABSTRACT FROM AUTHOR]

A recurrent wavelet first-order neural network (RWFONN) is proposed to select a desired attractor in a multistable erbium-doped fiber laser (EDFL). A filtered error algorithm is used to classify coexisting EDFL states and train RWFONN. The design of the intracavity laser power controller is developed according to the RWFONN states with the block control linearization technique and the super-twisting control algorithm. Closed-loop stability analysis is performed using the boundedness of synaptic weights. The efficiency of the control method is demonstrated through numerical simulations. [ABSTRACT FROM AUTHOR]

This work presents an experimental analysis and comparison of the performance of quasi-randomly distributed reflectors inscribed into a single-mode fiber as a sensing mirror both in C- and L-band. Single-wavelength emission has been obtained in either band when using these artificially controlled backscattering fiber reflectors in a ring-cavity fiber laser. Single-longitudinal mode operation with an optical signal to noise ratio (OSNR) of 47 dB and an output power instability as low as 0.04 dB have been measured when employing a C-band optical amplifier. When replaced by an L-band optical amplifier, a single-longitudinal mode behavior has also been obtained, showing an OSNR of 44 dB and an output power instability of 0.09 dB. Regarding their performance as fiber-laser sensing systems, very similar temperature and strain sensitivities have been obtained in both bands, comparable to fiber Bragg grating sensors in the case of temperature and one order of magnitude higher in the case of strain variations. [ABSTRACT FROM AUTHOR]

In this manuscript, the performance of a passively Q-switched fiber laser has been presented, where a segment of un-pumped erbium-doped fiber (EDF) is used as the saturable absorber (SA). We have taken an erbium and ytterbium (Er/Yb) co-doped double cladding fiber as the gain media for efficient pump absorption and checked the potential of the laser by changing the length of the in-house fabricated erbium-doped fiber saturable absorber (EFSA). For a fixed length of EFSA, variation of important system parameters such as output power, repetition rate, pulse width, etc, with the change of the pump power has also been reported. The laser has delivered pulses of a minimum duration of 1.35 µ s with maximum energy of 2.8 µ J. The repetition rate varies in the range from 24.8 kHz to 47 kHz with alteration of the length of the SA. The central wavelength of the output spectra is 1566 nm. [ABSTRACT FROM AUTHOR]

This work demonstrates a simple and economical route of preparing molybdenum trioxide/polydimethylsiloxane composite saturable absorber (MoO3-SA) for ultrashort pulse generation. The average size of MoO3 used in this work was about 10 μm and conveniently prepared using standard bath sonication. The MoO3-SA was fabricated by depositing MoO3 composite on tapered microfiber structure of 10 μm waist diameter via spin coating technique. The modulation depth, saturation fluence and non-saturable loss of the fabricated MoO3-SA were measured to be 4.02%, 28.3 μJ/cm2 and 33.02%, respectively. The employment of the MoO3-SA in erbium-doped fiber laser was able to generate mode-locked pulses at a threshold pump power of 64.1 mW with a central wavelength of 1559.87 nm and an ultrashort pulse duration of 748 fs. Micrometer-sized materials are far simpler in preparation which relaxes tight requirements for SA fabrication compared to advanced nanomaterials.

The growing field of photonics has seen significant developments in optical pulse fiber-based sensing technologies. In this research, a novel fiber Bragg grating using a Q-switched erbium-doped fiber laser source and innovative spider silk as a base material is presented, specifically designed for the detection of adulteration in pure kelulut honey. Kelulut honey has attracted much attention from Malaysian researchers as it is a highly prized, versatile local health remedy. During the experimental setup, concentrations of the adulterant isoglucose ranging from 0 % to 8 % and 10–50 % were intentionally added to the pure kelulut honey. The sensor showed remarkable sensitivity and detected subtle shifts in both the wavelength and radio frequency spectrum. The experimental results obtained emphasize the effectiveness of the proposed sensor and demonstrate its exceptional sensitivity in detecting adulteration in pure kelulut honey. This inherent property makes the derived pulse fiber laser sensor a promising tool for various applications in clinical detection and diagnosis as well as in the food industry. The results presented here not only contribute to the field of photonics but also have the potential to advance the quality control and authenticity assessment of kelulut honey in various fields. [Display omitted] • Developed a highly sensitive FBG sensor using a spider silk saturable absorber for adulteration detection in kelulut honey. • Demonstrated the effectiveness of a Q-switched pulse erbium-doped fiber laser in enhancing the detection sensitivity. • The sensor shows exceptional sensitivity in detecting kelulut honey adulteration, promising for clinical, diagnostic, and food industry applications. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a configuration of a passive Q-switched Erbium-doped fiber laser (EDFL) using a Lutetium Oxide (Lu2O3) thin film as a saturable absorber (SA) is experimentally implemented to generate high pulse energy with a high signal to noise ratio. A stable Q-switched pulse train is initiated at the input pump power of 30.442mW, and a maximum pulse energy of 16.11 nJ is obtained at an output power of 0.97 mW, which confirms the stability of the pulses. It was possible to increase the repetition rate of the Q-switched laser from 31.25 to 60.2 kHz as the pump power was raised from 30.442 mW to 71.652 mW. Moreover, the pulse width decreased from 11.4 µs to 4.27 µs and 66.4 dB of the received signal-to-noise ratio at the radio frequency spectrum was achieved.

In this paper, a new chaotic system is proposed by adding a magnetron memristor to an erbium-doped fiber laser circuit, and its dynamical characteristics are analyzed. A special periodic coexistence attractor phenomenon was discovered during the analysis, which affects the dynamical characteristics of the system by changing the time parameters of the AC power supply and it is controllable. Finally, the chaotic system is implemented by constructing an equivalent analog circuit. Theoretical analysis and simulation results show that the new erbium-doped fiber laser chaotic system has good dynamical characteristics and it is easy to implement. Meanwhile, the rich dynamical characteristics of the system provide a basis for its application in image encryption and other fields.

• A highly stable narrow linewidth erbium-doped fiber laser was proposed. • The self-injection locked mechanism was utilized in the ring-cavity fiber laser. • The cascaded Type Ⅱ fiber rings cavity filter was used to keep single-longitudinal-mode output. • The maximum wavelength drift was 0.0041 nm and the maximum peak power fluctuation was kept at a low level of 0.16 dB. • The minimum linewidth at a 0.002 s was 1.82 kHz. Narrow linewidth erbium-doped fiber lasers (EDFLs) hold in significant potential optical fiber sensing, wavelength multiplexing transmission, and optical fiber communication. However, many EDFLs produced outputs with linewidth in several kHz level. Therefore, a high optical signal-to-noise ratio (OSNR), narrow linewidth single-longitudinal-mode (SLM) EDFL was proposed and investigated in this work. The EDFL utilized a combination of compound-ring cavity filter and a self-injection locked mechanism to generate a stable SLM output with an OSNR greater than 72 dB. The maximum wavelength drift and maximum peak power fluctuation over 60 min were maintained at low values of 0.0041 nm and 0.16 dB. Moreover, a narrow linewidth of 1.82 kHz at a measuring time of 0.002 s was realized. Furthermore, the research also investigated output power variations with different pump powers, relaxation oscillation, and the dependence of output central wavelength on the axial strain. [ABSTRACT FROM AUTHOR]

• First demonstration of gamma-alumina (γ-Al 2 O 3) in mode-locked fiber laser systems. • γ-Al 2 O 3 coated tapered fiber with 7.3 % modulation depth is presented at 1.56 μm. • Ultrashort soliton pulses of 622 fs and 942 fs are recorded in C- and L-band wavelengths. • The damage threshold of SA is greater than 8.49 GW/cm2 and 3.57 GW/cm2 pumping intensities at 1.56 μm and 1.61 μm, respectively. This work demonstrates femtosecond pulse generations in C- and L-band regimes utilizing a gamma-aluminum oxide/polydimethylsiloxane saturable absorber (γ-Al 2 O 3 /PDMS-SA) via mode-locking technique. The γ-Al 2 O 3 /PDMS-SA has a 7.3% modulation depth and a moderate saturation intensity of 303 MW/cm2, and estimated damage threshold of greater than 8.49 and 3.57 GW/cm2 pumping intensities in C- and L-band wavelengths, respectively. In the C-band laser cavity, the generated mode-locked pulse delivered a low threshold of 28.7 mW and an ultrafast width of 622 fs. Meanwhile, a higher threshold of 108.6 mW and 942 fs pulse width were measured in the L-band laser cavity centered at 1611 nm. These demonstrations showcase a versatile feature of γ-Al 2 O 3 as a light-absorbing material that generates ultrashort pulses in a wideband wavelength range, which could benefit future research on the metastable state of aluminum-based materials within the field of ultrafast photonics. [ABSTRACT FROM AUTHOR]

• This paper proposes a wavelength tunable ring cavity erbium-doped fiber laser based on Fabry Perot filter fabricated by hydrofluoric acid corrosion for stretch sensing. • In the design of the laser, hydrofluoric acid is employed for chemical etching to prepare the F-P cavity, and tapering is applied to the F-P cavity to enhance sensitivity. In this study, the erbium-doped fiber laser with a ring cavity and a Fabry-Perot (F-P) filter was proposed and experimentally verified. In the design of the laser, hydrofluoric acid was employed for chemical etching to prepare the F-P cavity, and tapering was applied to the F-P cavity to enhance sensitivity. The experimentally prepared F-P filter was placed in the resonant cavity and served as a frequency-selective device for the fiber laser. At a laser threshold of 48 mW, we obtained a single-wavelength laser output at 1565.28 nm, with a 3 dB linewidth of 0.29 nm. To evaluate the stretching sensing performance of the EDFL system, we performed stretching of the F-P filter. The experimental results demonstrated that within a stretching length range of 0 to 3 mm, we could obtain a single-wavelength laser that could be tuned from 1559.57 to 1567.04 nm, corresponding to a tuning range of 7.47 nm. The laser showed a sensitivity of 2.73 nm/mm and a goodness of fit 0.999. Monitoring the stability of a single-wavelength laser within 30 min, the signal-to-noise ratio was greater than 27.212 dB, and the power fluctuation was less than 0.712 dB. Additionally, the polarization controller was adjusted to obtain two different dual-wavelength lasers with a power fluctuation of less than 0.71 dB. [ABSTRACT FROM AUTHOR]

With the rapid development of ultrafast photonics, the need for optical modulators is expanding. In particular, the optical modulator with a high damage threshold and the ability to generate multiple soliton states. This has prompted an ongoing search for optical modulators based on two-dimensional (2D) materials. Therefore, in this work, a novel 2D material Cr 2 Sn 2 Te 6 (CSnT) with modulation depth of 6.17% and saturation intensity of 15.97 MW/cm2 is prepared as saturable absorber (SA). The nonlinear optical absorption characteristics and pulse modulation applications of CSnT are showed in the Erbium-doped fiber laser (EDFL). The fundamental frequency mode-locked operation and the second harmonic mode-locked operation are realized simultaneously in the ring cavity. Moreover, CSnT SA has a high damage threshold and high stability, the damage threshold reaches 467 mW and the signal-to-noise ratio (SNR) is higher than 70 dB. The experimental findings demonstrate that the CSnT-based saturable absorber possesses remarkable nonlinear optical properties, indicating its considerable potential in the realm of ultrafast photonics. • CSnT was prepared as a saturable absorber for generating passively mode-locked in an Er-doped fiber laser. •The second harmonic mode-locked operation based on CSnT SA is realized for the first time. (with reference to current literature). • The passive mode-locked fiber laser based on CSnT SA has high SNR and damage threshold. [ABSTRACT FROM AUTHOR]

In this work, we have experimentally demonstrated the ultrafast laser in Erbium-doped fiber laser using MoS _2 as saturable absorber. The MoS _2 SA in this work is prepared by bottom-up method. A three-electrode configuration is used to perform the electrodeposition to coat the MoS _2 onto conductive film. The MoS _2 saturable absorber is incorporated into the fiber laser system to induce mode-locking operation centered at 1560.8 nm. The proposed saturable absorber has achieved pulse width of 1.47 ps, with highest average pulse energy of 0.44 nJ and repetition rate of 1.88 MHz. The venture of electrodeposition coated MoS _2 thin film as saturable absorber is potentially to pave the foundation toward the sustainable industry, innovation and infrastructure.

As a member of the MXene family, tungsten carbide (WC), with its unique physical structure and excellent optical properties, possesses enormous development potentials in ultrafast optoelectronics. In this letter, A WC film saturable absorber (SA) is successfully demonstrated to induce passive Q-switching in an erbium-doped fiber laser (EDFL). The WC nanoparticles (NPs) are synthesized by a hydrothermal method. Stable Q-switched pulses are generated at 1558 nm with a threshold pump power of 141 mW, after inserting the prepared WC film into the EDFL ring cavity. As the pump power ranges from 141 mW to 193 mW, the repetition rate increases from 32.34 kHz to 35.8 kHz, while the pulse duration decreases from $5.5~\mu \text{s}$ to $4.16~\mu \text{s}$. When the pump power reaches a maximum power of 193 mW, the corresponding maximum pulse energy and output power are 81 nJ and 2.9 mW, respectively. To our best knowledge, this is the first report of utilizing WC as SA to achieve Q-switched pulses. Our research results provide a new reference for the realization of pulsed laser using MXene materials and reveal that WC has immense applications in nonlinear optics and ultrafast laser technology, which greatly broadens the frontier of materials for optoelectronic techniques. [ABSTRACT FROM AUTHOR]

Metal nanomaterials have promising applications in ultrafast photonics due to their broadband operation, large third-order nonlinear susceptibility, and ultrafast recovery time. We realized a Q-switched pulsed erbium-doped fiber laser based on a silver nanoplate polyvinyl alcohol film as a saturable absorber. This film, with a modulation depth of 15.7%, was integrated into a fiber laser by means of a sandwich structure. We obtained Q-switched pulses in the 1.5-μm band, which plays an important role in telecommunications and atmospheric detection. Stable Q-switched pulses were obtained at the pump power of 135 mW, with a single pulse energy of 33.8 nJ, a pulse width of 2.3 μs, a repetition rate of 62.4 kHz, and a signal-to-noise ratio of about 45 dB. When increasing the pump power up to a maximum value of 246 mW, the maximum single pulse energy of 57.8 nJ was achieved. This study first demonstrates the potential of silver nanoplates as saturable absorbers in generating stable laser pulses with high energy.

As a member of transition metal dichalcogenides (TMDs), NbTe 2 has a work function of 5.32 eV and a band gap of 0 eV at the Fermi level, which enables it to possess broadband absorption characteristics and has huge potential in optoelectronic devices. In this work, a combination of liquid phase exfoliation (LPE) and optical deposition methods (ODMs) were used to fabricate a NbTe 2 saturable absorber (SA). Based on the NbTe 2 SA, a ring passive mode-locked erbium-doped fiber laser (PML-EDFL) was constructed by adding NbTe 2 SA into the laser cavity. A switchable single- to multiwavelength (dual/triple/quadruple) conventional soliton (CS) and a bound-state soliton (BS) were observed for the first time. The results reveal that NbTe 2 SA has excellent saturable absorption characteristics (modulation depth of 2.6%, saturation intensity of 177.4 MW/cm 2 , and unsaturated loss of 63.8%) and can suppress mode competition and stabilize multiwavelength oscillation. This study expands the applications of NbTe 2 nanosheets in ultrafast optoelectronics. The proposed switchable PML-EDFL has extensive applications in high-capacity all-optical communication, high-sensitivity optical fiber sensing, high-precision spectral measurements, and high-energy-efficiency photon neural networks.

A stable, single, and dual-wavelength erbium-doped fiber laser (EDFL), based on two Mach–Zehnder interferometers (MZIs), arranged in a cascade configuration, was proposed for experimental purposes. Both MZIs were assembled by splicing a capillary hollow-core fiber (CHCF) section between two multimode fibers (MMFs) segments. The novelty of this single and dual-wavelength EDFL is that the switchable operation of the laser is achieved by thermally tuning the interference pattern of one MZI and not by adjusting the polarization state inside the fiber ring cavity. The maximum measured value of SNR was 58.9 dB for the single and dual-wavelength laser emissions. Moreover, the stable output power exhibited by this EDFL, in terms of minimal power and wavelength fluctuations, at 0.05 dB and 10 pm, was detected during the single and dual-wavelength operation. It is worth noticing that switching is achieved at exact wavelength locations with a separation of 1.8 nm and not randomly, as reported by other works. These features make this switchable EDFL an appealing candidate for application in optical fiber communication systems and fiber sensing.

In this study, we have experimentally demonstrated the sodium carbonate (Na₂CO₃) thin-film as a saturable absorber (SA) for Q-switched laser generation in erbium-doped fiber laser (EDFL) cavity. The Na₂CO₃ powder was embedded in polyvinyl alcohol (PVA) to fabricate the thin film. The Na2CO3 was then employed in an EDFL cavity for passively generating Q-switched pulses with a minimum pulse width of 1.2 µs and maximum repetition rate of 94.7 kHz. The fundamental frequency of 94.7 kHz had the signal to noise ratio of 73.51 dB, which indicates the pulses were stable. The Q-switched laser operated at center wavelength of 1560 nm. [ABSTRACT FROM AUTHOR]

We have experimentally reported aluminum zinc oxide (AZO) as a novel saturable absorber to generate a mode-locked laser operating in dark pulsed regime. The D-shaped fiber was first prepared by side polishing a single-mode fiber to the 1 dB insertion loss. The AZO was dissolved in isopropyl alcohol and then deposited onto the D-shaped fiber by drop casting method. By carefully optimizing the polarization of the cavity, a dark pulse was achieved, which remained stable within the pump power of 65.7–101.35 mW. Pulse width was 220 ns, and the pulse repetition rate was 1.85 MHz. [ABSTRACT FROM AUTHOR]

This work presents a dual-wavelength C-band erbium-doped fiber laser assisted by an artificial backscatter reflector. This fiber-based reflector, inscribed by femtosecond laser direct writing, was fabricated into a single mode fiber with a length of 32 mm. The dual-wavelength laser obtained, centered at 1527.7 nm and 1530.81 nm, showed an optical signal-to-noise ratio over 46 dB when pumped at 150 mW. Another feature of this laser was that the power difference between the two channels was just 0.02 dB, regardless of the pump power, resulting in a dual emission laser with high equalization. On the other hand, an output power level and a central wavelength instability as low as 0.3 dB and 0.01 nm were measured, in this order for both channels. Moreover, the threshold pump power was 40 mW. Finally, the performance of this dual-wavelength fiber laser enhanced with a random reflector for sensing applications was studied, achieving the simultaneous measurement of strain and temperature with sensitivities around 1 pm/με and 9.29 pm/°C, respectively.

A recurrent wavelet first-order neural network (RWFONN) is proposed to select a desired attractor in a multistable erbium-doped fiber laser (EDFL). A filtered error algorithm is used to classify coexisting EDFL states and train RWFONN. The design of the intracavity laser power controller is developed according to the RWFONN states with the block control linearization technique and the super-twisting control algorithm. Closed-loop stability analysis is performed using the boundedness of synaptic weights. The efficiency of the control method is demonstrated through numerical simulations.

• A highly stable single-longitudinal-mode erbium-doped fiber laser was proposed. • A novel mode-selection filter, composed of two Type-Ⅱ fiber rings and a 1.5 m SA was used to realize SLM output. • The maximum wavelength drift was not observed and the maximum peak power fluctuation was kept at a low level of 0.16 dB. • The minimum linewidth at an integration time of 0.005 s was 2.8809 kHz. Single-longitudinal-mode (SLM) fiber lasers have the advantages of stable output, long coherence length, and low noise. However, several fiber lasers still maintain multiple longitudinal mode outputs. Thus, a highly stable SLM erbium-doped fiber laser (EDFL) was proposed and investigated. The dual-ring compound cavity (DRCC) filter, composed of two Type-Ⅱ fiber rings, and a 1.5 m unpumped erbium-doped fiber (EDF) was used as a mode-selection filter. The mode-selection capability of the DRCC filter and unpumped EDF was investigated and discussed theoretically and experimentally. The proposed EDFL could generate stable SLM output with an optical signal-to-noise ratio of ∼ 64 dB over 60 min. The maximum wavelength drift was not observed on an optical spectrum analyzer and the maximum peak power fluctuation was kept at a low level of 0.16 dB. The output power variations with different pump powers, the relative intensity noise, the relaxation oscillation, and the linewidth at different integration times were investigated. Furthermore, the performance of the proposed EDFL acted as a strain sensor and temperature sensor with sensitivities of 1.0 pm/με and 11.4 pm/℃ were also discussed. [ABSTRACT FROM AUTHOR]

In this study, carbon nanoparticles (CNPs) were experimentally investigated as novel saturable absorbers (SAs) capable of delivering strong ultrashort pulses in a passively Q-switched fiber laser. Carbon nanoparticles produced by candle burning and laser ablation can act as saturable absorbers (SAs). In addition, the nonlinear saturable absorption properties of the two synthetic CNPs in telecommunication region (1.5 μm) are investigated. Nonlinear optical measurements show that both SAs have good saturable absorption properties with average modulation depths of about ∼1 and 5 % at 1560 nm. These candle soot carbon nanoparticles (CSC-np) and laser ablation carbon nanoparticles (LAC-np) based SAs, can be used as a building blocker for the generating of stable Q-switched pulses in the near-infrared region. The shortest pulse duration measured with CSC-np and LAC-np are 5.62 and 3.87 μm, respectively. The pulse energy, peak power and SNR were also compared with both SA types at the highest pump power. The damage threshold and long-term stability of the CSC-cn SA and LAC-np were also explored. To the best of the author's knowledge, it is the first comparison of performance and long-term stability of EDFL based on two experimental techniques CSC-np and LAC-np based SAs. These results indicate that LAC-np SA provide have several advantages, including a high damage threshold, good saturable absorption, and optimum stability over a long time compared to CSC-np SA. [ABSTRACT FROM AUTHOR]

We have successfully demonstrated the soliton mode-locked pulse generation in a 77 m long erbium-doped fiber laser (EDFL) cavity using Poly(3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) as a saturable absorber (SA). The prepared PEDOT:PSS SA film exhibits excellent optical characteristics with large saturable absorption of 40% and low saturation intensity of 0.17 MW/cm2, appropriate for the soliton mode-locking generation. The fundamentally mode-locked EDFL operates at 1568.55 nm central wavelength, 2.465 MHz repetition frequency, a 3.06 nm 3-dB bandwidth and 4.46 nJ highest pulse energy. • Mode-locked erbium-doped all-fiber laser using PEDOT: PSS saturable absorber. • PEDOT:PSS SA film exhibits a large saturable absorption of 40%. • The laser produced a soliton pulse train at 1568.55 nm. • The repetition rate and pulse duration are 2.465 MHz and 870 fs, respectively. [ABSTRACT FROM AUTHOR]

We propose a point-by-point inscription method for fiber Bragg grating (FBG) fabrication using a femtosecond pulsed laser focused through a fiber polyimide coating, realizing a 2-μm-wavelength-band FBG. A femtosecond laser acts as the inscription laser, focused by a 63× oil lens. A first-order FBG was fabricated with a grating interval of 700 nm. The 15-μW pulsed laser was focused directly on the fiber core through the polyimide coating and cladding. A first-order FBG for 2004.8-nm light with more than 56% reflectances was fabricated. High wavelength sensitivity and linearity of the FBG were demonstrated by temperature and strain-sensing testing. The first-order FBG of 2004.8 and 2000.2 nm resonant wavelengths could be realized simultaneously through parallel inscription method in 3000 μm long grating area.

The saturable absorber device based on the MAX phase titanium aluminum carbide (Ti3AlC2) deposited onto D-shaped fiber has successfully activated a pulsed laser at a center wavelength of 1557 nm. The elemental composition and vibrational modes of the saturable absorber were analyzed using energy-dispersive x-ray spectroscopy and Raman spectroscopy for chemical analysis and structure imaging. Strong saturable absorption of 2% and a non-saturable absorption of 49.2% at the 1.55-µm, confirmed its ability to generate pulses in the near-infrared wavelength spectrum. The nanosecond laser owns a pulse width of 146.7 ns, a repetition rate of 3.44 MHz, and a signal-to-noise ratio of 54.4 dB. By varying the laser diode pump from 35-90 mW, a stable short-pulsed laser was generated with the highest single pulse energy of 1.57 nJ, which corresponded to the output power of 5.4 mW. This demonstration shows the potential of MAX phase Ti3AlC2 as a saturable absorber in an all fiber-based laser cavity. [ABSTRACT FROM AUTHOR]

In this paper, a configuration of a passive Q-switched Erbium-doped fiber laser (EDFL) using a Lutetium Oxide (Lu2O3) thin film as a saturable absorber (SA) is experimentally implemented to generate high pulse energy with a high signal to noise ratio. A stable Q-switched pulse train is initiated at the input pump power of 30.442mW, and a maximum pulse energy of 16.11 nJ is obtained at an output power of 0.97 mW, which confirms the stability of the pulses. It was possible to increase the repetitionrate of the Q-switched laser from 31.25 to 60.2 kHz asthe pump power was raised from 30.442 mW to 71.652 mW. Moreover, thepulse width decreased from 11.4µs to 4.27µs and 66.4dB of the received signal-to-noise ratio at the radio frequency spectrum was achieved. [ABSTRACT FROM AUTHOR]

In recent years, two‐dimensional materials have been widely used in the field of optics due to their unique nonlinear optical properties, broadband saturation absorption and ultrafast recovery time. MXene Ti3C2Tx is a kind of emerging two‐dimensional materials with large modulation depth, high damage threshold, and excellent electrical conductivity with near zero bandgap structure. However, MXene has seldom been applied in ultrafast photonics, especially the generation of ultrastable soliton molecules. In this paper, MXene is prepared and applied in the erbium‐doped fiber laser. The nonlinear optical properties of MXene Ti3C2Tx are studied experimentally. The center wavelength, 3‐dB bandwidth, fundamental frequency and the pulse duration of the conventional soliton are 1566.1 nm, 1.21 nm, 6.09 MHz and 993 fs, respectively. By adjusting the polarization state and pump power, the soliton molecules can be obtained in the laser cavity. Especially, two kinds of soliton molecules with CW peak and without CW peak are observed, respectively. Experimental results show that MXene saturable absorber (SA) can bear a high pump power. This work demonstrates that MXene Ti3C2Tx can be used as an excellent SA. Hence, we believe that this kind of optical material has many applications such as optical communication, optical logic gates and nonlinear devices, etc. [ABSTRACT FROM AUTHOR]

An erbium-doped fiber laser with all-fiber Mach–Zehnder interferometer (MZI) and tunable filter was proposed and experimentally demonstrated. In the designed fiber laser, 6 m C-band erbium-doped fiber was selected as a gain medium; the MZI comprised two waist-enlarged fiber bitapers. In the experiment, the laser threshold was 93 mW, whereas a switchable single-longitudinal-mode laser was realized within 1519.7–1564.6 nm by adjusting the tunable filter and the line interval was less than 2.5 nm; for single-wavelength laser, the peak power difference of each line was less than 4 dB, and the power fluctuation was less than 0.77 dB within 10-min scan time. A stable and switchable dual-wavelength laser was realized, the wavelength spacing of each dual-wavelength laser was less than 0.7 nm, the side-mode suppression ratio was more than 30.2 dB, and the power shift was less than 0.39 dB. The laser’s 3-dB linewidth was less than 0.1 nm.

A tunable spacing dual-wavelength Q-switched fiber laser is experimentally demonstrated based on a fiber Bragg grating tunable device incorporated in an erbium-doped fiber laser (EDFL). The system utilizes two identical fiber Bragg gratings (FBGs) at 1547.1 nm origin to enable two laser lines operation. The wavelength separations between two laser lines are controlled by fixing one of the FBGs while applying mechanical stretch and compression to the other one, using a fiber Bragg grating tunable device. The seven steps of wavelength spacing could be tuned from 0.3344 to 0.0469 nm spacing. Pulse characteristics for both close and wide spacing of dual-wavelength Q-switched fiber laser are successfully being recorded. The findings demonstrate the latest idea of dual-wavelength fiber laser based on FBG tunable device, which offers a wide range of future applications.

This work demonstrates a passively Q-Switched fiber laser employing graphite oxide as a saturable absorber, generating tunable microsecond pulses with kHz repetition rates, pulse energies of up to 15.54 nJ and the pulse-to-pulse timing jitter of 46.14 fs. The graphite oxide samples were obtained by recycling the graphite present in Li-ion batteries utilized in cell phone devices through a chemical separation and subsequent oxidation process. Sample characterization employing X-ray diffraction, solid-state nuclear magnetic resonance and Raman spectroscopy showed that the produced graphite oxide exhibited a homogeneously oxidized structure. These results indicate that applications in the physics of pulsed lasers can benefit from the recycling of lithium batteries, directing the process of discarding spent batteries. [ABSTRACT FROM AUTHOR]

• We demonstrated a QML EDFL incorporating a microfiber and the NPR technique. • The microfiber enables stable QML operation under large pump power fluctuations. • The average single-pulse energy is 2.35 times higher than that attained with CW mode-locking. • The microfiber's customizable size creates a potential for QML pulse regulation. We demonstrated a dual-loss-modulated Q-switched mode-locked (QML) erbium-doped fiber laser based on the nonlinear polarization rotation (NPR) technique with a microfiber. The microfiber served as both a highly nonlinear medium and a saturable absorber, which together with the NPR technique enables stable QML operation under significant pump power fluctuations. We evaluated the nonlinear properties of microfibers with different waist diameters. A maximum QML envelope energy of 467.15 nJ is achieved, corresponding to an average single-pulse energy of 4.06 nJ beneath the Q-switched envelope, which is 2.35 times higher than the maximum pulse energy attained with dissipative soliton mode-locking under similar pump power. In addition, the QML laser was verified by numerical simulation based on the coupled Ginzburg-Landau equation. The microfiber's customizable size enables significant variations in non-linear and saturable absorption characteristics, creating the potential for QML pulse regulation. This research provides novel insights for designing QML lasers. [ABSTRACT FROM AUTHOR]

We have successfully accomplished a Q-switched and mode-locked pulse in an Erbium-doped fiber (EDF) laser cavity by integrating a new composite material silver doped Indium Selenide (Ag/In 2 Se 3)-based saturable absorber (SA). Ag/In 2 Se 3 film was synthesized by using pulsed laser ablation and a common dry cast method to form a free-standing thin film SA. This SA device exhibits a nonlinear optical property of modulation depth, saturable intensity, and non-saturable loss of 2.27%, 847.20 MW/cm2, and 16.82% respectively. By implementing Ag/In 2 Se 3 film into the EDF laser cavity, a Q-switched pulsed began to generate at a threshold pump power of 27.63 mW. Then as 100 m single-mode fiber (SMF) was implemented into the EDF laser cavity, a traditional soliton pulse began to appear with 1.873 MHz, at the threshold pump power of 76.63 mW with a narrow pulse width of 3.11 ps, and remarkable temporal stability, as demonstrated by a signal noise ratio (SNR) of 79.62 dB. The peak power of 2.61 kW was recorded. This contribution further verifies the improved optical qualities of the Ag/In 2 Se 3 composite and offers a new possibility for developing broadband SA devices for various photonics applications. [ABSTRACT FROM AUTHOR]

• Generation of mode-locked in EDFL and THDFL by employing rGO/ZnO as a SA. • The rGO/ZnO based SA exhibit modulation depth of 4.06 % in the 1.5 µm. • The rGO/ZnO based SA exhibit modulation depth of 46.23 % in the 2.0 µm. • A pulse width of 0.92 ps and pulse energy of 135.79 pJ were produced in the 1.5 µm. • A pulse width of 1.36 ps and pulse energy of 144.15 pJ were produced in the 2.0 µm. Our research focuses on synthesizing reduced graphene oxide/zinc oxide (rGO/ZnO) nanocomposite using hydrothermal techniques, which we then utilized as a saturable absorber (SA) to generate ultrashort pulses at wavelengths of 1.5 μm and 2.0 μm. A balanced twin detector approach investigated the nonlinear optical properties of rGO/ZnO nanocomposite, giving modulation depths of 4.06 % and 46.23 % at the 1.5 µm and 2.0 µm wavelength ranges, respectively. Stable mode-locked pulses with picosecond pulse widths and megahertz repetition rate were obtained after inserting the rGO/ZnO-coated arc-shaped fiber into an erbium-doped fiber laser (EDFL) and Thulium/Holmium-doped fiber laser (THDF) cavities. The pulse width and repetition rate differ between EDFL and THDFL, with EDFL generating an output soliton with a pulse width of 0.92 ps and a repetition rate of 18.19 MHz, and THDFL producing a pulse width of 1.36 ps and a repetition rate of 12.14 MHz. Upon assessment of their long-term stability, it was found that both generated lasers exhibited remarkable resilience, with signal-to-noise ratio (SNR) values surpassing 50 dB. Our study indicates the extraordinary broadband nonlinear features of rGO/ZnO nanocomposite. It presents a new opportunity to develop ultrashort nonlinear devices utilizing rGO/metal oxide-based nanocomposites. [ABSTRACT FROM AUTHOR]

• Conversion from Q-switched to bright-dark soliton pair operation can be realized in an InSb based fiber laser. • The repetition frequency of the Q-switched pulse can be increased from 4.0145 kHz to 10.623 kHz. • The stable bright-dark soliton pair has a high SNR of 59 dB. In this experiment, stable Q-switched pulses and bright-dark soliton pairs were realized in an InSb based erbium-doped fiber laser. Firstly, when the pump power was between 70 and 115 mW, a stable passive Q-switched operation with a central wavelength of 1565.38 nm was achieved, and the signal-to-noise ratio (SNR) was about 37 dB. As the pump power increased, the repetition frequency of the Q-switched pulse can be increased from 4.0145 to 10.623 kHz. When the pump power was increased to the range of 185 to 450 mW, stable bright-dark soliton pairs mode-locked operation was realized, and the two peaks of the spectrum were located at 1568.67 and 1569.34 nm, respectively. The pulse repetition rate was 3.419 MHz, and the SNR was about 59 dB. This research will broaden the application of InSb in ultrafast optics and nonlinear optics. [ABSTRACT FROM AUTHOR]